1.3 - Fire Extinguishers

A fire extinguisher is a device used to control or extinguish fire. Fire extinguishers are classified according to their extinguishing medium.

Common Types of Fire Extinguishers

Type and label colour	Use
Water — red	Flammable solids such as cloth, paper and wood
Foam — cream	Flammable solids such as wood and paper; flammable liquids or gases such as oil, paint and natural gas
Carbon dioxide — black	Electrical appliances, gas and vapour
Dry powder — blue	All types of fires

Classes of Fire and Suitable Fire Extinguishers

Class and burning substance	Suitable extinguisher
A — flammable solids except metals, such as wood, paper and cloth	Water, foam, dry powder
B — liquids such as petrol, kerosene, diesel, paint and varnish	Foam, dry powder, carbon dioxide
C — gases such as LPG, LNG and oxygen	Dry powder, carbon dioxide
D — metals such as magnesium, aluminium, sodium and potassium	Dry powder
E — electrical appliances	Dry powder, carbon dioxide
F — fats and cooking oils	Dry powder, carbon dioxide

Other Firefighting Equipment

ABC fire extinguisher

• Can be used for all types of fires except fires caused by metals and gases that will not allow explosion.
• Is not harmful to humans or animals.
• Does not pollute the soil.
• Is easy to maintain—at least once a year.
• Produces moisture that lasts longer and prevents fire from spreading again.

Fire blanket

• Made of two layers of glass fibres.
• Extinguishes small or moderate fires that are difficult to extinguish with water.
• Extinguishes fire on a victim when wrapped around the victim’s body.

Sand and water

• Sand can extinguish an early-stage fire.
• Water can extinguish fire except fire resulting from oil.

Method of Using a Fire Extinguisher

1. Remove the safety pin and keep the fire extinguisher upright.
2. Aim the nozzle at the base of the fire from about 2.0–2.5 metres away.
3. Squeeze the handle on top of the fire extinguisher.
4. Spray evenly over the entire fire source while sweeping the nozzle from side to side.

Simple Fire Safety Checklist

• Install smoke detectors.
• Provide an emergency plan and emergency route from every room; ensure all occupants know and practise using them.
• Use light bulbs with suitable wattage.
• Keep heat-producing electrical appliances at least 1 metre from curtains, furniture and other flammable equipment.
• Do not charge electronic equipment on a bed or leave it charging unattended.
• Check electrical wiring periodically for damage that could cause a short-circuit fire.
• Do not make unauthorised extensions or overload electrical circuits.
• Keep matches and lighters out of children’s reach.
• Store containers of flammable liquid safely, away from fire sources and children.
• Keep one dry-powder or ABC fire extinguisher at home.

Audit of Fire Extinguishers at School

Record and check:

• the types of fire extinguishers;
• the expiry date of each fire extinguisher;
• the pressure reading on each fire extinguisher;
• the number of fire extinguishers according to type; and
• the location of each fire extinguisher on the school emergency route plan.

Creating a Simple Fire Extinguisher

Problem: A kitchen contains flammable substances such as flour, sugar and oil. The presence of fuel can cause a fire at home.

Design brief: Create a working simple fire extinguisher using materials available at home.

STEM process

1. Ask questions and identify the problem.
2. Develop and use a model.
3. Plan and carry out an inquiry-based investigation.
4. Analyse and interpret the data obtained.
5. Use mathematical and computational thinking.
6. Construct explanations and design solutions.
7. Debate and discuss based on evidence.
8. Obtain, evaluate and communicate information.